When the Croatian repair network EV Clinic posted an unusually blunt warning on X about ‘catastrophic’ failure rates in Tesla Model 3 and Model Y NMC battery packs built by LG Energy Solution in Nanjing (China), the message rippled quickly across the EV community, picked up by sites like Electrek, ArenaEV, and others. But it also raises eyebrows.
The post claiming that “cell degradation in these packs is often so severe that in over 90% of cases we receive, cell-level repair is not possible,” suggested that Tesla vehicles equipped with them may struggle to reach roughly 150,000 miles (about 240,000 km), far short of the 250,000 miles (around 400,000 km) many Teslas achieve.
How representative are the data?
Such assertions strike a nerve in a sector where real-world lithium-ion battery cell performance has generally proven more robust than early predictions suggested. At the same time, the forcefulness of the claim raised an immediate counter-question. How representative are the data behind it, and how much weight should the public give to warnings issued by a private repair lab rather than a manufacturer or regulator?
EV Clinic’s X thread painted a dark portrait of these Chinese-made NCM811 packs, contrasting them sharply with Panasonic’s US-made NCA packs, which Tesla used during the same production period.
Although LG Energy Solution is a South Korean company, the NMC811 cells at the center of the debate are manufactured at its Nanjing, China, plant. The ‘811’ designation means the cathode is made of roughly 8 parts nickel, 1 part manganese, and 1 part cobalt for high energy density.
According to EV Clinic, many LG packs they opened showed extensive, homogeneous degradation across modules, rather than the occasional failing cell typically found in Panasonic units.
The lab-cited internal resistance values were dramatically higher than expected, suggesting the packs were already at or near end-of-life. From their perspective, repairing such a battery—whether by replacing cells or even whole modules—would be a short-lived fix.
Likely to fail again and cost the shop more in warranty returns than it could ever recoup. They claim to be losing tens of thousands of euros each month just by trying to determine whether these batteries can be salvaged at all.
Interestingly, Tesla’s other China-sourced batteries — the LFP packs supplied by CATL — have so far built a reputation for being exceptionally robust, with degradation figures that consistently outperform those of many NMC-based chemistries.
Self-taught specialist?
The warnings would be easier to interpret if EV Clinic were an OEM, an academic lab, or a regulated testing institute. But it isn’t any of those. It is, instead, an independent repair and reverse-engineering operation built around a small but technically ambitious team.
At its center is founder Vanja Katić, a self-taught specialist who has earned a following among EV enthusiasts for his teardown work and deep-dive diagnostics. His Zagreb-based workshop operates under the EV Clinic brand but is legally incorporated as POSH TRADE d.o.o., one of several franchise-like entities that carry the name in Europe.
EV Clinic’s own website underscores that structure: the brand operates separately from the repair shops that use its name, and it explicitly disclaims responsibility for the work performed by these local entities.
This fragmented setup is one of the reasons some observers approach EV Clinic’s bold technical statements cautiously. The company is obvious within enthusiast circles, collaborates with green-tech events, and produces detailed breakdowns of battery failures and powertrain issues.
Yet it maintains an unusually opaque posture about who exactly constitutes its ‘expert team,’ beyond Katić himself. There are no published engineer profiles, no formal affiliations with universities or regulators, and no peer-reviewed studies underpinning the claims.
Much of its reputation instead comes from years of community-level word of mouth and the trust of customers who say the lab has solved problems that manufacturer service centers refused to touch.
Not a marginal player
At the same time, EV Clinic is not a marginal player. Regional business media in Croatia have described it as a leader in the technical side of e-mobility. High-profile EV figures, including YouTuber Bjørn Nyland, have visited their facilities to document repair processes.
The company’s blog and video content offer such a granular look at circuit boards, cell chemistry behavior, BMS logic, and failure patterns that few doubt the team’s hands-on experience. Even among seasoned battery engineers, it is hard to fake years of teardown documentation.
No public comments
So far, neither Tesla nor LG Energy Solution has issued any public comment addressing EV Clinic’s claims or the subsequent media coverage. No recall notices, technical bulletins, or regulatory filings have surfaced that acknowledge unusual failure patterns in LG’s NCM811 packs.
The silence is notable, given the specificity and severity of the allegations. Still, it also reflects a larger uncertainty: without independent, large-scale fleet data, automotive manufacturers rarely respond to isolated third-party findings. For now, EV Clinic’s warnings stand unchallenged but also unverified by the companies that built or supplied the batteries in question.
Outside the Croatian lab’s reports, the landscape is surprisingly thin. There are scattered owner anecdotes on forums and social media groups describing premature degradation, range drops, or charging irregularities in LG-equipped Model 3 and Model Y vehicles.
Yet, none of these accounts rise to the level of a clearly documented failure trend. No academic studies, consumer-protection agencies, or independent diagnostic networks have published data corroborating a systemic issue with LG-made Tesla packs.
Definitive conclusions?
That leaves the EV Clinic findings in a narrow but essential space: serious enough to warrant attention, but not broad enough to draw definitive conclusions about the fleet at large.
This leaves the industry—and Tesla owners—facing a dilemma. EV Clinic is credible enough that its warnings cannot simply be dismissed. Yet the conclusions it draws are based on a particular sample: vehicles that arrive at an independent repair lab because they are already exhibiting problems.
That introduces selection bias, which the lab itself does not deny. Without access to a broader fleet overview, it is impossible to know whether the failures they observe reflect an inherent design weakness or merely the statistical reality that a portion of any battery population will fail under certain conditions.
For owners of Tesla models equipped with LG NMC811 packs, the situation is uncomfortable. Some may indeed face premature degradation. Others may drive hundreds of thousands of kilometers without incident.
For now, the risk is concentrated in a specific slice of the fleet: China- and Berlin-built Model 3 and Model Y Long Range and Performance cars using LG’s NMC811 cells, most of which are sold in China itself and in export markets such as Europe (including Belgium) and parts of the Asia-Pacific region.
The point, for now, is uncertainty. Independent labs like EV Clinic often serve as early-warning signals in the EV ecosystem, but their role is not to replace systematic scientific inquiry.
